SECTIONAL TRANSACTIONS .—A, Af. 451 
Wednesday, September 13. 
Prof. Dayton C. MILLer.—The ether-drift experiment, and the absolute 
motion of the solar system and the orbital'motion of the earth (10.0). 
Major A. G. Cuurcu, D.S.O.—Recent developments in television (10.30). 
Visit to Messrs. Taylor, Taylor and Hobson’s Optical Works. 
PAPERS OF INTEREST TO THOSE ENGAGED IN 
TECHNICAL PHYSICS (Af). 
Friday, September 8. 
Mr. H. Warren.—The talking film in industry (11.0). 
Mr. L. J. Davies.—Hot cathode gas discharge tubes (11.40). 
A description of various types of industrial hot cathode discharge tubes 
such as ‘ Thyratrons,’ gas discharge lamps, etc., with particular reference to 
the design of cathodes for various applications. 
Mr. J. T. RANDALL.—Spectroscopy in the service of industry (12.20). 
Monday, September 11. 
Dr. C. H. Spiers.—Some physical problems of leather manufacture (12.0). 
Mr. H. Braptey.—(1) A study of water absorption and vapour absorption 
by leather and other shoe materials, with a note on the importance of 
these processes in shoe manufacture. 
Solutions of the diffusion equation with various boundary conditions 
and their application to experiments with leathers immersed in water 
or exposed to various atmospheric humidities. Absorption isotherms 
—absorption hysteresis—air permeability—porosity—the relation of these 
properties to the absorption and adsorption processes. Absorbed moisture 
and thermal conductivity. 
The importance of this work in modern shoe factory development. 
(2) The testing of flexible sheet materials by hydrostatic or pneumatic 
pressure. 
A discussion of the method of test as applied to paper, textile fabrics, 
metal foil and sheet, leather, rubber, and a presentation of experimental 
results and calculations bearing on the theory of the subject. 
Tuesday, September 12. 
Discussion on High voltages and high vacua (10.0) :-— 
Mr. C. R. BurcH.—On the design and operation of oil condensation 
pumps. 
The operation of a condensation pump on low vapour pressure organic 
fluids, such as vacuum distillates from mineral oils, is influenced by con- 
siderations which do not arise when mercury is used as working fluid. 
